Conventionally, as a humidity controller capable of at least a humidifying operation, there is one that is composed of an adsorption element whose honeycomb base member has an air passage supporting an adsorbent on its surface, and a heat pump apparatus using a refrigerant circuit (for example, see patent document 1 and patent document 2). This humidity controller is equipped with a pair of adsorption elements each capable of adsorbing moisture in air and discharging moisture to air. The humidity controller is configured to humidify the inside of a room by alternately changing the following two operations: an operation in which the controller adsorbs moisture from first air with a first adsorption element and discharges the moisture outdoors, and at the same time, gives moisture to second air with a second adsorption element and supplies the moisture to the inside of the room; and an operation in which the controller adsorbs moisture from the first air with the second adsorption element and discharges the moisture outdoors and at the same time, gives moisture to the first air with the first adsorption element and supplies the moisture to the inside of the room.
In the above-mentioned controller, in order to heat air that is to be supplied to the inside of the room before flowing the air to the adsorption element, the above-mentioned heat pump apparatus is used.    Patent document 1: JP 2003-227626    Patent document 2: JP 2003-232540
However, the controller needs to be provided with the adsorption elements and the heat pump apparatus, which poses a problem that the controller becomes complex in configuration and large-sized.